Dysregulated hematopoiesis and a progressive neurological disorder induced by expression of an activated form of the human common beta chain in transgenic mice

Previously we described activating mutations of h beta(c), the common signaling subunit of the receptors for the hematopoietic and inflammatory cytokines, GM-CSF, IL-3, and IL-5. The activated mutant, h beta(c)FI Delta, is able to confer growth factor-independent proliferation on the murine myeloid cell line FDC-P1, and on primary committed myeloid progenitors. We have used this activating mutation to study the effects of chronic cytokine receptor stimulation. Transgenic mice were produced carrying the h beta(c)FI Delta cDNA linked to the constitutive promoter derived from the phosphoglycerate kinase gene, PGK-1. Transgene expression was demonstrated in several tissues and functional activity of the mutant receptor was confirmed in hematopoietic tissues by the presence of granulocyte macrophage and macrophage colony-forming cells (CFU-GM and CFU-M) in the absence of added cytokines. All transgenic mice display a myeloproliferative disorder characterized by splenomegaly, erythrocytosis, and granulocytic and megakaryocytic hyperplasia. This disorder resembles the human disease polycythemia vera, suggesting that activating mutations in h beta(c) may play a role in the pathogenesis of this myeloproliferative disorder. In addition, these transgenic mice develop a sporadic, progressive neurological disease and display bilateral, symmetrical foci of necrosis in the white matter of brain stem associated with an accumulation of macrophages. Thus, chronic h beta(c) activation has the potential to contribute to pathological events in the central nervous system.

The modelling of froth zone recovery in batch and continuously operated laboratory flotation cells

This paper proposes an integrated methodology for modelling froth zone performance in batch and continuously operated laboratory flotation cells. The methodology is based on a semi-empirical approach which relates the overall flotation rate constant to the froth depth (FD) in the flotation cell; from this relationship, a froth zone recovery (R,) can be extracted. Froth zone recovery, in turn, may be related to the froth retention time (FRT), defined as the ratio of froth volume to the volumetric flow rate of concentrate from the cell. An expansion of this relationship to account for particles recovered both by true flotation and entrainment provides a simple model that may be used to predict the froth performance in continuous tests from the results of laboratory batch experiments. Crown Copyright (C) 2002 Published by Elsevier Science B.V. All rights reserved.

Effect of functional gain on satisfaction with medical rehabilitation after stroke

Objective: To examine the association between gain in motor and cognitive functional status with patient satisfaction 3-6 mo after rehabilitation discharge. Design: Patient satisfaction and changes in functional status were examined in 18,375 patients with stroke who received inpatient medical rehabilitation. Information was obtained from 144 hospitals and rehabilitation facilities contributing records to the Uniform Data System for Medical Rehabilitation and the National Follow-up Services. Results: Data analysis revealed significant (P < 0.05) differences in satisfaction responses based on whether information was collected from patient self-report or from a family member proxy, and the two subsets were analyzed separately. Logistic regression revealed the following significant predictors of satisfaction for data collected from stroke patients: cognitive and motor gain, rehospitalization, who the patient was living with at follow-up, age, and follow-up therapy. In the patient-reported data subset, compared with patients who showed improved cognitive or motor functional status, those with no change, respectively, had a 31% and 33% reduced risk of dissatisfaction. In addition, rehospitalized patients had a higher risk of dissatisfaction. For the proxy reported data subset, significant influences on satisfaction were health maintenance, rehospitalization, stroke type, ethnicity, cognitive FIM(TM) gain, length of stay, and follow-up therapy. Conclusions: Ratings of satisfaction with rehabilitation services were affected by change in functional status and whether the information was collected from patient rating or proxy response.